Listvenite Formation During Mass Transfer into the Leading Edge of the Mantle Wedge: Initial Results from Oman Drilling Project Hole BT1B

Abstract This paper provides an overview of research on core from Oman Drilling Project Hole BT1B and the surrounding area, plus new data calculations, constraining processes in Tethyan subduction zone beneath Samail ophiolite. The area is underlain by gently dipping, broadly folded layers allochthonous Hawasina pelagic sediments, metamorphic sole ophiolite, Banded Unit peridotites at base mantle section. Despite reactivation some faults during uplift Jebel Akdar Saih Hatat domes, preserves tectonic “stratigraphy” Cretaceous zone. Gently dipping listvenite bands, parallel to peridotite banding contacts between sole, replace near basal thrust. Listvenites formed less than 200°C (poorly constrained) depths 25–40 km reaction with CO 2 ‐rich, aqueous fluids migrating greater depths, derived devolatilization subducting sediments analogous clastic Formation, 400°–500°. Such could form important reservoirs for subducted . Listvenite formation was accompanied ductile deformation serpentinites listvenites—perhaps facilitated fluid‐rock reaction—in a process that lead aseismic regions. Addition H O wedge, forming listvenites, caused large increases solid mass volume rocks. may have been accommodated fractures as result changes, mainly serpentinization front.